The measure, passed this month by the San Francisco Board of Supervisors, goes into effect in October. About 3,000 commercial buildings in the city, amounting to more than 160 million square feet, are affected, says GreenBiz.

Under the measure, starting in October, owners of commercial properties larger than 50,000 sq. ft. must file an annual report summarizing the energy performance of their buildings. Similar reporting for commercial building from 10,000 sq. ft. to 50,000 sq. ft. is slated to begin in 2013. Starting next year, energy audits also will be required every five years.